1. Field
One or more embodiments of the present invention relate to a battery pack.
2. Description of Related Art
In general, secondary batteries may be discharged and recharged, unlike a primary battery, which may not be recharged. Secondary batteries are used as energy sources of small-sized devices, such as cellular phones, laptop computers, and camcorders, and medium-large sized devices, such as electric cars, hybrid electric cars, electric bicycles, and as an uninterruptible power supply (UPS).
A lithium secondary battery is an example of a secondary battery. The lithium secondary battery may be classified as a can-type secondary battery, which has a cylindrical or square shape depending on the shape of a case accommodating a battery unit, or a pouch-type secondary battery having flexibility.
A secondary battery may be classified as a liquid electrolyte battery or a polymer electrolyte battery according to the type of electrolyte used therein. In general, a battery using a liquid electrolyte is referred to as a lithium ion battery, and a battery using a polymer electrolyte is referred to as a polymer battery.
Conventionally, a secondary battery allows a bare cell accommodating an electrode assembly to be coupled to a protection circuit module (PCM). An electrode terminal of the PCM is electrically coupled to electrode taps of a conventional bare cell by using, for example, an arc welding method, a laser welding method, or a spot welding method. However, the above conventional welding methods have difficult welding conditions and may cause a safety problem.
Accordingly, these welding methods require a worker to be skilled and educated about safety. However, a welding process may still be risky despite such requirements. Such a potential risk causes difficulty in safely manufacturing and supplying a battery pack.